Electrochemical Research On Graphene Composites

In recent years, environment and human health has become more and more important. Developing clean environment friendly energy is the key way to solve this problem, Also, the development of rapid, accurate, steady biochemical sensor play a significant role to human health.In our work, we applied heteroatom doped graphene and graphene/mental oxide nanoparticles composite as electrochemical sensor and ORR catalyst.Chapter 1:IntroductionIntroduce the present situation of graphene, the synthesis method of graphen and its composite and the function of graphene composite.Chapter 2:Facile synthesis of Boron-doped grahene and its effect on the simultaneous electrochemical determination of ascorbic acid, dopamine, and uric acidA facile, effective approach for fabricating boron-doped graphene (B-rGO) and nitrogen-doped graphene (N-rGO), are demonstrated by hydrothermal treating graphite oxide with borane tetrahydrofuran complex solution, hydrazine hydrate respectively. Scanning electron microscope (SEM) characterizations reveal that the as-prepared N-RGO and B-RGO both have a flake-like structure. X-ray photoelectron spectroscopy (XPS) analysis demonstrates that boron and nitrogen atoms can be successfully doped into graphene structures. Due to its particular structure and unique electronic properties, the resultant B-rGO, N-rGO both exhibit excellent electrocatalytic activities towards the oxidation of ascorbic acid, dopamine and uric acid. After comparison, we found B-rGO progressed significantly better electrochemical properties and showed better sensibility for the simultaneous determination of the above three bio-moleculesChapter 3:Controlled growth cerium oxide nanoparticles on reduced graphene oxide for oxygen catalytic reductionIn this paper, a facile and simple strategy was developed for in-situ growth cerium oxide nanoparticles on reduced graphene oxide (rGO) through thermal treatment of the Ce3+-doped graphene oxide(GO) under nitrogen atmosphere. Through regulation the thermal treatment temperature, cerium oxide nanocrystals can be easily controlled growth in accompany with the reduction of GO. The morphology and chemical composition of as-synthesized CeO2/rGO at different temperature are characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The as-synthesized nanocomposites show electrocatalytic activity toward the oxygen reduction reaction (ORR) in alkaline solution. Especially, the cerium oxide nanoparticles/rGO nanocomposites with thermal treatment temperaure of 750℃ possess excellent electrocatalytic ability with a dominating four-electron pathway, high tolerance of methanol and long-term operation stability due to the well exfoliationof graphene and perfect crystalline structure of cerium oxide. Compared to the commercial Pt/C catalyst, the synergistic effect of the fast electron transport of rGO and the high electrocatalytic activity of cerium oxide nanocrystals makes the nanocomposites as advanced, non-precious electrocatalysts for ORR.Chapter 1:Non-enzymatic hydrogen peroxide electrochemical sensor based on Eu2O3/Yb2O3 nanoparticles graphene compositeA new type of electrochemical sensor, Eu2O3/Yb2O3 nanoparticles graphene composite,was developed for in-situ growth Eu2O3/Yb2O3 nanoparticles on reduced graphene oxide (rGO) through thermal treatment of the Eu3+/Yb3+-doped graphene oxide(GO) under nitrogen atmosphere. The morphology and chemical composition of as-synthesized Eu2O3/rGO and Yb2O3/rGO are characterized by scanning electron microscopy, X-ray diffraction spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. The as-synthesized nanocomposites play a great role in its sensing performance among for H2O2 detection. The electrochemical studies showed that the H2O2 sensor based on the Yb2O3/rGO nanocomposites exhibited an excellent detection performance with a wide linear range from 2x10-6 to 4x 10’3 M and a detection limit of 1x 10-6 M (S/N= 3).1These results demonstrate that nanocomposites have promising application in electrochemical sensors.